JPH07118332A - Method for recovering fluoromonomer - Google Patents

Abstract

PURPOSE:To efficiently and quantitatively extract and recover a fluoromonomer which is liq. at room temp. from a latex obtd. by the emulsion polymn. of the fluoromonomer by bringing the latex into contact with a specific fluorinous solvent. CONSTITUTION:An unreacted fluoromonomer which is liq. at room temp. [e.g. a fluorovinyl compd. of formula I (wherein a is 0-3; and b is 1-5) having a carboxylate group] is recovered from a latex obtd. by the emulsion polymn. of the monomer by bringing the latex into contact with a fluorinous solvent boiling at 10-250 deg.C and selected from the group consisting of hydrochlorofluorocarbons of formulas II and l. hydrofluorocarbons (e.g. C4F9C2B5), and fluorocarbons (e.g. C6F14). An unreacted liq. monomer in the latex is extracted and recovered with the solvent easily, efficiently, and quantitatively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering unreacted monomer contained in an emulsion polymerization latex of a fluorinated monomer which is liquid at room temperature.

[0002]

BACKGROUND OF THE INVENTION Fluorine-based polymers are emulsion polymerization, suspension polymerization,
Although produced by a method such as solution polymerization or bulk polymerization, emulsion polymerization is adopted because it has advantages such as high volumetric efficiency in a polymerization tank, low heat during polymerization and low torque during stirring. In emulsion polymerization, monomers that are gaseous at room temperature, such as tetrafluoroethylene, are easily recovered by purging after polymerization. However, the unreacted fluorinated monomer that is liquid at room temperature is contained in the produced latex, and especially monomers containing functional groups may be modified during latex aggregation and the recovery rate may decrease. Preferably.

Conventionally, a solvent of a fluorinated chlorinated saturated hydrocarbon is used for recovering a liquid fluorinated monomer, and the latex and the solvent are mixed and allowed to stand, and the monomer contained in the solvent separated into two layers is extracted. The method of collecting was adopted (Japanese Patent Publication No. 62-56886). However, although chlorofluorocarbons such as trichlorotrifluoroethane that have been conventionally used are easily available and inexpensive, they are said to have the potential to destroy the ozone layer in the atmosphere, and their use is limited, so application of alternative extraction solvents Has been requested.

[0004]

The object of the present invention is to solve the above-mentioned problems. That is, there is provided a method capable of quantitatively and efficiently extracting and recovering unreacted monomers contained in an emulsion polymerization latex of a fluorinated monomer that is liquid at room temperature. Further, the present invention provides a recovery method using an extraction solvent that does not damage the ozone layer.

[0005]

The present invention has a boiling point of 10 to 250 ° C. in recovering the unreacted liquid fluorinated monomer from a latex obtained by emulsion polymerization of a liquid fluorinated monomer at room temperature. And CF ₂ ClCF
₂ CFHCl, CF ₃ CF ₂ CHCl ₂ , at least one fluorine-based solvent selected from the group consisting of hydrofluorocarbons and fluorocarbons is brought into contact with the latex, and the unreacted monomer is extracted and recovered by the fluorine-based solvent. Provided is a method for recovering a characteristic fluorinated monomer.

The specific fluorine-based solvent in the present invention has a boiling point of 2 due to its recyclability and ease of handling at room temperature.
Those having a temperature of 0 to 200 ° C. are preferable, and those having a boiling point difference of 20 ° C. or more with the monomer are particularly preferable in view of the ease of distillation separation after extraction of the liquid fluorinated monomer. Specifically, the structures of the hadrofluorocarbon (HFC) and the fluorocarbon (FC) may be linear, branched, or cyclic, but the number of carbon atoms is 4 to 12 in HFC and FC. Ranges are preferred. HF
As C, C ₄ F ₉ C ₂ H ₅ , (CF ₃ ) ₂ CFCFH
CFHCF ₃ , C ₆ F ₁₃ H, C ₆ F ₁₃ C ₂ H ₅ and C ₈
At least one type of fluorine-based solvent selected from F ₁₇ C ₂ H ₅ and at least one type of fluorine-based solvent selected from Chemical Formula 2 as FC are particularly preferable because of their properties and industrial availability. These fluorine solvents can be used alone or as a mixed solvent.

[0007]

[Chemical 2]

In the extraction operation, the above-mentioned fluorine-containing solvent is usually added to the latex, and the mixture is stirred or shaken and then allowed to stand, and the fluorine-containing solvent containing the monomer is separated into the lower layer. In the extraction operation, the unreacted monomer can be quantitatively recovered by extracting the separated lower layer, adding the fluorine-based solvent newly, and repeating the above operation several times.

The mixing ratio of latex / fluorine solvent during the extraction operation is in the range of 20/1 to 1/10. If the mixing ratio of the fluorine solvent is increased too much, the number of extractions can be reduced, but It is not preferable because the monomer concentration becomes remarkably low and the apparatus volume during distillation recovery becomes large. On the other hand, if the mixing ratio of the fluorine-based solvent is too small, the number of extractions will increase, which is not preferable. More preferably 10/1
It is in the range of ½.

The extraction treatment of the present invention is applied to an emulsion polymerization type latex containing a fluorinated monomer which is liquid at room temperature. Examples of the liquid fluorinated monomer may include various ones, a carboxylic acid group, a sulfonic acid group,
A fluorinated monomer containing a functional group such as a phosphoric acid group in a pendant side chain, particularly a perfluoro-based monomer is preferable. The emulsion polymerization system is usually a copolymerization system of a specific liquid fluorinated monomer and a fluorinated ethylenically unsaturated monomer that is gaseous at room temperature.

The specific liquid fluorinated monomer suitable in the present invention is a carboxylic acid group or a carboxylic acid type functional group capable of being converted into a carboxylic acid group, or a sulfonic acid group or a sulfonic acid type functional group capable of being converted into a sulfonic acid group. An example is a fluorinated functional monomer (1) having a polymerization ability. It is usually desirable that the fluorinated functional monomer (1) is a fluorovinyl compound, particularly a perfluoro type, in consideration of the use and performance of the produced polymer.

Preferably, the monomer having a carboxylic acid type functional group has the general formula CF ₂ ═CF (OCF ₂ C
_{FCF 3) a O (CF 2} ) b COOCH 3 ( where, a in the formula is 0 to 3, b is fluorovinyl compound represented by from 1 to 5) are exemplified. A monomer having a sulfonic acid type functional group has a general formula CF ₂ ═CF (OCF ₂ CFCF
₃ ) _c O (CF ₂ ) _d SO ₂ F (provided that c in the formula is 0 to
3, and d is 1 to 5).

Next, as the fluorinated ethylenically unsaturated monomer (2), ethylene tetrafluoride, ethylene trifluoride chloride, propylene hexafluoride, ethylene trifluoride, vinylidene fluoride, vinyl fluoride are used. And the like, and is preferably a fluorinated olefin compound represented by the general formula CF ₂ ═CZY (wherein Z and Y are a fluorine atom, a chlorine atom, a hydrogen atom, or —CF ₃ ). Of these, perfluoroolefin compounds are preferable, and tetrafluoroethylene is particularly preferable.

In the present invention, each of the functional monomer (1) and the ethylenically unsaturated monomer (2) may be used in a combination of two or more kinds. Besides, other ingredients such as the formula C
H ₂ = CR ₄ R ₅ (wherein R ₄ and R ₅ represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aromatic nucleus), an olefin compound (3) represented by the formula CF ₂ = CFORf ( R
f represents a perfluoroalkyl group having 1 to 10 carbon atoms)
Such fluorovinyl ethers of the formula CF ₂ = CF-CF
= CF _2, wherein _{CF 2 = CFO (CF 2)} e OCF = CF
It is also possible to use one kind or two or more kinds of divinyl monomers such as ₂ (e is 1 to 4) in combination. Preferred representative examples of the olefin compound (3) include ethylene, propylene, butene-1, isobutylene, styrene, α-methylstyrene, pentene-1, hexene-1, and heptene-.
1,3-methyl-butene-1,4-methyl-pentene-
1, etc. Among them, use of ethylene, propylene, isobutylene and the like is particularly preferable from the viewpoint of production and performance of the produced copolymer. Further, it is possible to improve the mechanical strength when a copolymer obtained by using a divinyl monomer in combination is crosslinked to form a molded article such as a film.

The composition ratio of the functional monomer (1), the fluorinated olefin compound (2), and the olefin compound (3) and other components in the fluorinated polymer produced in the latex of the present invention is It is important because it is related to performance.

First, the amount of the functional monomer (1) present is directly related to the ion exchange capacity, but it is preferably 1 to 50 mol%, preferably 3 to 35 mol% in the copolymer. When the amount of the monomer (1) present is too large, the mechanical strength of the formed product such as an ion exchange membrane is impaired, and further, the ion exchange performance is deteriorated due to an increase in water content, and the amount is too small. The amount is not preferable because it does not exhibit an ion exchange function.

Thus, the remainder of the compound of (1) in the copolymer of the present invention is occupied by the other compounds of (2) and (3), but the olefin of (3). The abundance of the compound is important because it is greatly related to electrical, mechanical and chlorine resistance. Therefore, when the olefin compound (3) is used in combination, the molar ratio of olefin compound (3) / fluorinated olefin compound (2) is
Preferably 5/95 to 70/30, especially 10/90 to
60/40 is preferable. Further, when fluorovinyl ether or divinyl ether is used in combination, the proportion of the copolymer is preferably 30 mol% or less, more preferably about 2 to 20 mol%.

In the emulsion polymerization system of the present invention, the ion exchange capacity of the produced polymer is selected from a wide range of 0.5 to 2.2 meq / g dry resin. Even if the value is increased, the molecular weight of the produced copolymer can be increased, and therefore the mechanical properties and durability of the copolymer will not be reduced. The ion exchange capacity varies depending on the type of the copolymer even in the above range, but is preferably 0.8 meq / g dry resin or more, particularly 1.
The case of 0 meq / g dry resin or more is preferable from the viewpoint of mechanical properties and electrochemical performance as an ion exchange membrane. The molecular weight of the fluorine compound polymer obtained in the present invention, since the relationship between mechanical performance and film formability as an ion-exchange membrane is important, when viewed in the value of T _Q, 0.99
℃ or more, preferably 170 ~ 340 ℃, especially 180 ~ 3
The temperature is preferably about 00 ° C.

In the present specification, the term "T _Q " is defined as follows. That is, the temperature at which the volumetric flow rate of 100 mm ³ / sec related to the molecular weight of the copolymer is T
Defined as _Q. Here, the volumetric flow rate is such that the copolymer is pressurized at 30 kg / cm ² and the diameter is 1 mm and the length is 2 at a constant temperature.
The amount of the copolymer melted and flowed out from the orifice of mm is shown in the unit of mm ³ / sec.

The "ion exchange capacity" is as follows. That is, an H-type cation exchange resin membrane is
It was left to stand in HCl of 60 ° C. for 5 hours, completely converted to H-form, and washed sufficiently with water so that HCl did not remain. Then, 0.5 g of this H-type film was added to 0.1N NaOH 25
at room temperature in a solution of 25 cm ³ of water added to ³ cm ^3.
Let stand for days. The membrane is then removed and NaO in solution is removed.
It is determined by back titrating the amount of H with 0.1 N HCl.

In the present invention, the copolymerization reaction between the functional monomer and the fluorinated olefin compound is carried out in an aqueous medium. Usually, the amount of the aqueous medium used is 20/1 or less in terms of the weight ratio of the aqueous medium / functional monomer, preferably 10 /
It is better to control it to 1 or less. If the amount of the aqueous medium used is too large, the copolymerization reaction rate is significantly reduced,
It will take a long time to obtain a high copolymer yield. Further, if the amount of the aqueous medium is too large, it becomes difficult to achieve a high molecular weight when the ion exchange capacity is high. Furthermore, the following problems are recognized when a large amount of aqueous medium is used. For example, there are disadvantages in terms of work operation such as enlargement of reactor or separation and recovery of copolymer.

Next, in the present invention, it is preferable to adopt a copolymerization reaction pressure of 1 kg / cm ² or more. If the copolymerization reaction pressure is too low, the copolymerization reaction rate cannot be maintained at a level that is practically satisfactory, and it is difficult to form a high molecular weight copolymer. On the other hand, if the copolymerization reaction pressure is too low, the ion exchange capacity of the produced copolymer becomes extremely high, and the mechanical strength and the ion exchange performance tend to decrease due to an increase in water content. Incidentally, the copolymerization reaction pressure is preferably selected from 50 kg / cm ² or less in consideration of the reaction apparatus in industrial practice or work operation. It is possible to employ a copolymerization reaction pressure higher than this range, but it is not possible to proportionally improve the object of the present invention. Therefore, in the present invention, the copolymerization reaction pressure is optimally selected from the range of 1 to 50 kg / cm ² , preferably 3 to 30 kg / cm ² .

In the copolymerization reaction of the present invention, other conditions and operations other than the above reaction conditions can be adopted over a wide range without particular limitation. For example, as the copolymerization reaction temperature, an optimum value can be selected depending on the type of the polymerization initiation source, the reaction molar ratio, etc. However, usually, too high temperature or too low temperature is disadvantageous for industrial practice, and therefore 10 to 90 C., preferably about 20 to 80.degree.

In the present invention, it is desirable to select, as the polymerization initiation source, one that exhibits high activity at the above-mentioned suitable reaction temperature. For example, ionizing radiation that is highly active even at room temperature or lower can be adopted, but the method of using an azo compound or a peroxy compound is usually advantageous for industrial practice. The polymerization initiation source preferably adopted in the present invention is
Diacyl peroxide such as disuccinic acid peroxide, benzoyl peroxide, lauroyl peroxide, and dipentafluoropropionyl peroxide, which show high activity at about 10 to 90 ° C. under the copolymerization reaction pressure,
2,2-azobis (2-amidinopropane) hydrochloride,
Azo compounds such as 4,4-azobis (4-cyanovaleric acid) and azobisisobutyronitrile, peroxyesters such as t-butylperoxyisobutyrate and t-butylperoxypivalate, diisopropylperoxide Peroxydicarbonates such as oxydicarbonate, di-2-ethylhexyl peroxydicarbonate, hydroperoxides such as diisopropylbenzene hydroperoxide, inorganic peroxides such as potassium persulfate and ammonium persulfate and their redox systems Is.

In the present invention, the concentration of the polymerization initiator is 0.0001 to 3% by weight, preferably 0.0
It is about 1 to 2% by weight. By decreasing the initiator concentration, it becomes possible to increase the molecular weight of the produced copolymer, and it is difficult to maintain a high ion exchange capacity. If the initiator concentration is too high, the molecular weight tends to decrease, which is disadvantageous to the formation of a high molecular weight copolymer with a high ion exchange capacity. In addition, surfactants, dispersants, buffers, molecular weight modifiers and the like used in ordinary aqueous medium polymerization can be added.

In the present invention, the concentration of the produced copolymer is 4
It is suitable to carry out the control at a content of 0% by weight or less, preferably 30% by weight or less. If the concentration is too high, problems such as increased stirring load, heat removal difficulty, and insufficient diffusion of fluorinated olefin monomer are found.

As described above, in the latex obtained by emulsion polymerization in an aqueous medium, the fluorine-based solvent is added as described above to extract and separate the unreacted liquid monomer. In addition, unreacted substances of gaseous monomers such as tetrafluoroethylene can be easily separated and recovered by a purging method or the like. Next, an acid such as hydrochloric acid or sulfuric acid is added to the latex from which the unreacted monomer has been separated and recovered to coagulate the polymer. Other salting out,
Alternatively, well-known or known aggregating means such as freeze agglutination and mechanical agglutination can be adopted.

The coagulated polymer is thoroughly washed with water, and then the water is replaced with a water-soluble organic solvent such as methanol or acetone. After air-drying the polymer, 100 cm ³ is preferable to use the polymer 100 wt added 400～600Cm ³ or more methanol, more preferably it to process 1-50 hours adding sulfuric acid while stirring 20 ° C. or higher. Then, the polymer and methanol are separated, and when sulfuric acid is added, the polymer is washed with methanol to remove it, and then dried at 40 to 80 ° C. under reduced pressure to obtain a polymer.

According to the present invention, an ion exchange group-containing fluorinated polymer having a high ion exchange capacity and a high molecular weight and excellent in moldability by heating and melting can be obtained smoothly and advantageously.
For example, a fluorinated polymer that has just been copolymerized in an aqueous medium has a T _Q of more than 300 ° C. even when a functional monomer containing —COOR ₁ is used, but is subjected to a heat contact treatment with methanol or the like. By doing so, it is possible to lower T _Q to about 220 ° C. With a fluorinated polymer having a T _Q of 300 ° C. or higher, hot melt molding is extremely difficult and cannot be formed into a film or sheet, but the fluorinated polymer according to the present invention can be formed into a film or sheet by extrusion molding or the like. Can be easily molded.

The fluorinated polymer obtained in the preferred embodiment of the present invention can be formed into a film by an appropriate means. For example, if necessary, the functional group is converted into a carboxylic acid group by hydrolysis,
Such hydrolysis treatment can be performed before or after film formation. Usually, it is desirable to carry out hydrolysis treatment after film formation. Various kinds of film forming means can be adopted, and for example, known or well-known methods such as heat melting molding, latex molding, and casting molding by dissolving in a suitable solution can be appropriately adopted.

The ion exchange membrane made from the produced fluorinated polymer according to the present invention has various excellent performances and thus can be widely used in various fields, purposes and applications. For example, it is preferably used as a membrane for diffusion dialysis, electrolytic reduction fuel cells, and the like, especially in the field where corrosion resistance is required. Above all,
When used as a cation-selective membrane for alkaline electrolysis, it can exhibit high performance that cannot be obtained with conventional ion exchange membranes.

For example, the cation exchange resin membrane of the fluorinated polymer of the present invention divides the anode and cathode into an anode chamber and a cathode chamber, and an alkaline chloride aqueous solution is supplied to the anode chamber. Even in the case of a so-called two-chamber type tank which is electrolyzed to obtain an alkali hydroxide from the cathode chamber, 40% or more is obtained by electrolyzing at a current density of 5 to ²⁰ A / dm ² using a sodium chloride aqueous solution having a concentration of ² N or more as a raw material. It is possible to stably produce high concentration sodium hydroxide with high current efficiency of 90% or more for a long period of time. Further, electrolysis is possible at a low cell voltage of 4.5 V or less.

[0033]

【Example】

[Example 1] A 0.2-liter stainless steel autoclave was charged with 100 g of ion-exchanged water and C ₈ F ₁₇ COONH _4.
0.2 g, 0.5 g Na ₂ HPO ₄ .12 H ₂ O,
0.3 g of NaH ₂ PO ₄ .2H ₂ O, (NH ₄ ) ₂ S
0.026 g of ₂ O ₈ and CF ₂ ═CFO (CF ₂ ).
20 g of ₃ COOCH ₃ was charged and thoroughly degassed under liquid nitrogen. Then, the temperature was raised to 55 ° C., ethylene tetrafluoride was introduced into the system, and the pressure was maintained at 10.4 kg / cm ² .
After stirring for 3.3 hours, unreacted tetrafluoroethylene was purged to terminate the reaction. The produced copolymer is 20 mol% of the copolymerized CF ₂ ═CFO (CF ₂ ) ₃ COOCH _3.
The amount of latex produced was 15.5 g.

The latex contains unreacted CF ₂ ═CFO (C
Although it contains F ₂ ) ₃ COOCH ₃ , it is impregnated with polymer particles in the latex to form a uniform layer. 30 g of CF ₂ ClCF ₂ CHFCl (hereinafter referred to as HCFC225cb, boiling point 54 ° C.) is added to 100 g of the latex.
In addition, the mixture was shaken in a separating funnel for 10 minutes and then left standing for 30 minutes. After separating the lower HCFC225cb layer, the same amount of HCFC225cb was added again and the extraction operation was repeated.
When the extraction operation was performed 6 times, CF ₂ ═CFO was found by gas chromatography for both the HCFC225cb layer and the aqueous layer.
It was found that (CF ₂ ) ₃ COOCH ₃ was not detected and was quantitatively extracted. The extraction layers of HCFC225cb were collected and distilled to obtain CF ₂ = CFO (CF ₂ ) ₃ COOCH ₃
11.5 g was recovered.

[Example 2] HCFC225c was used as the extraction solvent.
An extraction operation was carried out in the same manner as in Example 1 except that C ₄ F ₉ C ₂ H ₅ (boiling point 68 ° C.) was used instead of _{b, and} unreacted CF ₂ ═CFO (CF ₂ ) ₃ COOCH ₃ Is 1
1.3 g was recovered.

Example 3 C ₆ F ₁₃ H as an extraction solvent
When an extraction operation was performed in the same manner as in Example 1 except that (boiling point 72 ° C.) was used, unreacted CF ₂ ═CFO (CF
₂ ) 1COg of ₃ COOCH ₃ was recovered.

Example 4 In a 0.2 liter stainless steel autoclave, 120 g of ion-exchanged water and C ₈ F were added.
₁₇ COONH ₄ to _{0. 42g, Na 2 HPO 4 ·} 12H
₂ O and 0. 6 g, the _{NaH 2 PO 4 · 2H 2 O} 0.3
5 g, 0.064 g of (NH ₄ ) ₂ S ₂ O ₈ and (CH
₃ ) 0.03 g of ₂ CHOH and CF ₂ ═CFO (C
12 g of F ₂ ) ₂ SO ₂ F was charged and sufficiently degassed under liquid nitrogen. Then, the temperature was raised to 60 ° C., ethylene tetrafluoride was introduced into the system, and the pressure was maintained at 11.7 kg / cm ² .
After stirring for 5.5 hours, unreacted tetrafluoroethylene was purged to terminate the reaction.

The resulting copolymer is a copolymerized CF ₂ ═C
A latex having a composition containing 13.7 mol% of FO (CF ₂ ) ₂ SO ₂ F, and the amount produced was 19.8 g. The latex contains unreacted CF ₂ ═CFO (CF ₂ ) ₂ SO ₂ F, but is impregnated with polymer particles in the latex to form a uniform layer. HC to 100 g of the latex
FC225cb (30 g) was added, and unreacted CF ₂ = CFO (CF ₂ ) ₂ SO ₂ F extraction layers were collected under the same extraction conditions as in Example 1, and CF ₂ = CFO (CF ₂ ) ₂ S was obtained by distillation.
4.1 g of O ₂ F was recovered. By repeating the extraction operation 6 times, CF ₂ ═CFO (CF ₂ ) ₂ SO _{2 was} obtained by gas chromatography for both the aqueous layer and the HCFC225cb layer.
It was found that F was not detected and was quantitatively extracted.

[Comparative Example 1] CF ₂ ClC as an extraction solvent
An extraction operation was performed in the same manner as in Example 1 except that FCl ₂ (ozone depletion potential: 0.8) was used.
11.1 g of F ₂ = CFO (CF ₂ ) ₃ COOCH ₃ was recovered.

[Comparative Example 2] CH ₂ Cl ₂ as an extraction solvent
When an extraction operation was performed in the same manner as in Example 1 except that the above was used, the aqueous layer became cloudy even after standing and the CH ₂ Cl ₂ layer was not sufficiently separated, and CH ₂ Cl ₂ was partially contained in the aqueous layer. It was found to dissolve.

[Comparative Example 3] CHCl ₂ C as an extraction solvent
The extraction operation was performed in the same manner as in Example 1 except that F ₃ was used, but the aqueous layer and the CHCl ₂ CF ₃ layer were not separated even after standing.

[Comparative Example 4] CFCl ₂ C as an extraction solvent
An extraction operation was performed in the same manner as in Example 1 except that H ₃ was used, but the aqueous layer and the CFCl ₂ CH ₃ layer were not separated even after standing.

[0043]

Industrial Applicability The liquid unreacted fluorinated monomer in the latex is quantitatively highly efficiently and easily recovered by the extraction operation with a specific fluorine-based solvent.

Claims (6)

[Claims] 1. A boiling point of 10 to 250 in recovering the unreacted liquid fluorinated monomer from a latex obtained by emulsion polymerization of a liquid fluorinated monomer at room temperature.
C., CF ₂ ClCF ₂ CFHCl, CF ₃ CF ₂
At least one kind of fluorine-based solvent selected from the group consisting of CHCl ₂ , hydrofluorocarbon and fluorocarbon is brought into contact with the latex, and the unreacted monomer is extracted and recovered by the fluorine-based solvent. Recovery method. 2. A fluorinated monomer that is liquid at room temperature has a carboxylic acid group or a carboxylic acid type functional group that can be converted into a carboxylic acid group, or a sulfonic acid group or a sulfonic acid type functional group that can be converted into a sulfonic acid group. The method according to claim 1, which is a monomer. 3. A monomer having a carboxylic acid type functional group,
The general formula CF ₂ = CF (OCF ₂ CFCF ₃ ) _a O (CF
₂ ) _b COOCH ₃ (where a is 0 to 3 and b is 1
The recovery method according to claim 2, which is a fluorovinyl compound represented by 4. A monomer having a sulfonic acid type functional group,
The general formula CF ₂ = CF (OCF ₂ CFCF ₃ ) _c O (CF
₂ ) _d SO ₂ F (where c is 0 to 3 and d is 1 to 5 in the formula)
The recovery method according to claim 2, which is a fluorovinyl compound represented by 5. The hydrofluorocarbon is C ₄ F ₉ C.
₂ H ₅ , (CF ₃ ) ₂ CFCFHCFHCF ₃ , C ₆ F
_{5. At} least one selected from the group consisting of ₁₃ H, C ₆ F ₁₃ C ₂ H ₅ and C ₈ F ₁₇ C ₂ H _5.
Either of the collection methods. 6. The recovery method according to claim 1, wherein the fluorocarbon is at least one kind selected from Chemical formula 1. [Chemical 1]